According the Wiley: "In some of the new letters, ATF has begun listing the following “objective design features” when making its evaluations:
https://comms.wiley.law/8/3583/octo...ports-and-may-require-nfa-registration(2).asp
[video=youtube;dkYlQz7KPVE]http://www.youtube.com/watch?v=dkYlQz7KPVE[/video]
- Incorporation of rifle sights;
- Utilization of "rifle caliber ammunition" (both 5.56mm and 7.62mm have been considered as such);
- Incorporation of “rifle-length barrel;”1
- The “weapon’s heavy weight;”
- Ability to accept magazines that range in capacity from 20 rounds to 100 rounds, “which will contribute to the overall weight of the firearm”; and
- Overall length of the weapon which “creates a front-heavy imbalance when held in one hand.”"
https://comms.wiley.law/8/3583/octo...ports-and-may-require-nfa-registration(2).asp
[video=youtube;dkYlQz7KPVE]http://www.youtube.com/watch?v=dkYlQz7KPVE[/video]